"Poisonous environment"
Several DC insiders,
deciding not to run again, have cited the "poisonous environment" or "toxic politics" this year.
What's unusual this year? This is one of the rare years when the American people pay close attention to DC, ignore the standard talking points, and make decisions based on real self-interest.
Thus we know clearly what the politicians mean by "poison".
Americans are "poison" to them.